ZHONG Guanglei (1995-), male, Doctoral candidate. E-mail: zhongguanglei@mail.sdu.edu.cn
The growth of crystal in the initial stage have an impact on the quality of crystal in the subsequent growth. In this paper, the surface and micropipes morphology of SiC in the initial stage of growth was investigated by optical microscopy. At 8×104 Pa and 1 800-2 100 ℃, the growth step appears on the seed crystal surface due to the atomic migration. Also, the micropipes seriously disturbe the movement of normal step flow, and a circular pit occurs around the micropipes. And no polytype transformation occurs at the micropipes. At 2×104 Pa and 2 150-2 300 ℃, multiple SiC nuclei are formed in the center of the seed crystal surface. Obvious stress regions appear near the crystal edge due to the existence of micropipes. The stress is mainly in the region close to the micropipes and towards the crystal edge, indicating that the step flow moves from the center to the edge. In addition, SiC substrate was also characterized by atomic force microscopy, indicating that atom steps with different orientations appear on the substrate surface, which may originate from the step morphology of the crystal grown in the initial stage.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |